The pair, who starred in The Mary Tyler Moore Show together before Harper got her own spin-off show Rhoda, have been friends for decades and are facing this cruel blow together.

"I'm absolutely devastated by this news," Moore said in a statement. "Valerie has given so much joy, laughter and love to the world. I join her fans and send much love and positive thoughts to her and her family during this difficult time."

Harper shared the details of the phone call in which she gave her bestie the sad news.

"She said, 'What's up?' I said, 'It's incurable cancer.' She said, 'Val, I'm so sorry,'" Harper told People. Before ending their phone call, "Mary said, 'One day at a time. That's how we've got to live our lives. That's the best we can do."